1. Field of the Invention
The invention relates to optical navigation device and more particularly to image device and method thereof for using linear image sensor.
2. Description of the Prior Art
The optical metrology is generally applied today, especially with the image sensing technology which is adopted to determine the navigation and velocity. The specific applications are including optical mice, hand scanning device, and similar products.
The general optical navigation device comprises a light source adopted to emit light onto surface, and a detector adopted to receive the light reflected from the surface. The detector is usually a two-dimensional array formed by discrete optically sensitive element. A time series of images of detectable surface feature is acquired when the device moves relative to the surface. Thus, imaging processing is adopted to compare the variations between the presently and previously stored information. Then the displacement and motion direction are detected from the peak position of cross-correlation method between the outputs within the time series.
However, two-dimensional sensor array costs more than linear sensor array due to using more optically sensitive element. Besides, with the rapid advancement of image processing technology, the effective detector needs to increase the operation speed. Obviously, reducing the optically sensitive element can achieve the goal directly.
The inventor of the present invention recognizes the above shortage which should be improved and special effort has been made to research this field. The present invention is presented with reasonable design to resolve the problems mentioned above.